Tapping machine



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TAPPING MACHINE Filed April 27, 1945 17 Sheets-Sheet 11 ALBERT E1. ELNEEUE 1:1

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TAPPING MACHINE Filed April 27, 1945 1'7 Sheets-Sheet 15 ALBERT 5 EIN'EEUE l3 7 a amixm Dec. 12, 1950 A. s. GINSBURG 2,533,451

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TAPPING MACHINE Filed April 27, 1945 17 Sheets-Sheet 16 ALBERT E1. FINEJEIUEE,

Patented Dec. 12, 1950 TAPPING MACHINE Albert S. Ginsburg, Chicago, 111., assignor to La I Salle Designing Company, Chicago, 111., a partnership Application April 27, 1945, Serial No. 590,560

28 Claims. (01. -429) This invention relates to a machine, more particularly to a machine for threading the stepped interior of the breech ring of large caliber guns.

The breech ring of most large caliber guns is provided with a threaded interior and such interior is closed by a threaded breech block. To permit rapid closing of the breech block in the breech ring, the interior oi such breech ring is provided with an interrupted thread. However, to provide the greatest strength possible, it was found necessary to provide several series of threaded steps to obtain the maximum possible threaded engagement with the breech block. Such procedure is necessary in order to withstand the tremendous breech pressures developed in large caliber guns.

To any one skilled in the art it is readily apparent that threading each of these steps is a rather formidable task. Present day methods for machining the threads on the stepped interior of a breech ring utilize a conventional lathe which has been modified somewhat to permit this threading operation. Such modification consists primarily in employing a cam arrangement in the compound rest to efiect transverse movement of the threading tool at the proper interval to clear each successive step on the interior of the breech ring. Threading of the stepped interior is otherwise accomplished in a more or less conventional manner.

Thus it is readily appreciated that threading such a stepped surface is necesasrily a slow procedure. Further, the accuracy of threads cut in this fashion is limited entirely by the accuracy of the lathe performing the operation. As there are numerous moving parts and consequently points of wear on such a machine, the accuracy of the finished product often leaves something to be desired, Furthermore, the skill of the operator of the threading machine likewise determines to a very considerable degree the accuracy of the finished product.

Obviously if the threads on the interior of the breech ring are not cut to a high degree of perfection, the corresponding threads of the breech block will not be in proper engagement. Then in order to obtain the close fit between the ens gaging threads necessary to withstand the tremendous pressure that such threads must resist, a very considerable amount of hand scraping and lapping will then be required to effect such fit. I

Accordingly,-it is an object of this invention to provide a machine for threading interior surfaces of a workpiece, for example, the stepped interior surfaces of the breech ring of a large caliber gun.

Another object of this invention is to provide a machine which will accurately thread the stepped interior of a breech ring of a large caliber gun to finished dimensions, eliminating any need for hand finishing.

Another object of this invention is to provide a step threading machine which automatically advances the thread cutting tool from one step to the next upon completion of the threading of the preceding step.

Another object of this invention is to provide a breech ring threading machine that can conveniently accommodate a variety of diiferent diameter breech rings by the mere substitution of difierent' sizes of thread cutting tools.

Another objectof this invention is to provide a breech ring threading machine capable of cutting threads of different pitch on the stepped interior of breech rings.

A particular object of this invention is to provide a cutting tool assembly on a rotating spindle wherein the cutting tool may be incrementally advanced outwardly with respect to the spindle by increments as small as a thousandth of an inch.

Another object of this invention is to provide,

improved locking means to rigidly position a sliding work table upon the bed of a machine tool.

which I Fig. 1 is a perspective view of the machine utilized for threading the stepped interior of the breech ring of large caliber guns.

Fig. 2 is a side-elevational view of the breech ring threading machine.

Fig. 3 is a top-elevational view of the breech ring threading machine.

Fig. 4 is a front-elevational View of the breech 7 ring threading machine. Fig. 5 is a cross-sectional view taken along the plane 55 of Fig. 2.

Fig. 6 is a partial, longitudinal-sectional viewplunger.

The specific nature of the invention as well asother; objects and advantages thereof will clearly appear from a description of a preferred embodi; ment as shown in the accompanying drawings in-' Fig. 9 is a partial, cross-sectional view taken along the plane 9- of Fig. '7 showing the details of the adjustable bed for positioning the breech ring within the breech ring fixture.

Fig. 10 is an enlarged detailed view of the cutter head shown in assembled relation wherein the front end of the cutter is shown.

Fig. I1 .is :a:deta'iled view of the cutter ihe'ad similar to that shown in Fig. 10 but rotated 90 degrees to show a side view of the cutter and the position of the micro switch with relation to the cutter.

Fig. 12 is a cross-sectional view taken along the plane I2-I2 of Fig. 10.

Fig. 13 is a bottom elevationa'lwiew of Fig. 11.

Fig. 14 is a top elevational view of Fig. 10 showing the keys utilized to secure the pilot ito the cutter head.

Fig. 15 is a partial, longitudinal-sectional view taken along the plane I5I5 of Fig. 1

Fig. 1'6 is a "top elevati'onal view of the box utilized "to house the cutter feeding mechanism shown with the top removed"toshowthesarrangement of such mechanism.

Fig. .1 7 is -a longitudinal-=sectiona'l View taken along the plane II-II of Fig. B6.

Fig. 18 is "a 'longitudinabsection'al view taken along the plane I8-'I 8 of 'Fig. 16.

Fig. '19is a cross-sectional view of the driving arm u'tilized'to-e'fiect reciprocation o'f the'spindle and spindle body showing the arrangement of the hydraulic cylinder and "indexing pin and in additionfthe amount of angular rotation Y of such driving arm necessary in threading each step-of the stepped interior :of the 'breech ring.

Fig. 20 is a partial,1ongitudinal-sectional"view taken along-the -plane 2U-'2Il*of Fig. zshowing the arrangement of the wedges utilized to lock the sliding table against sideways movement.

Fig. 21 is a longitudinal-sectionalView of the cutter head centering fixture taken along the plane 21- 2 I of 'Fi'gfi'l.

Fig. 22 isa 'top-elevational view of Fig. 21.

Fig. 23 is a partial, bottomelevational view of head 3 showing the arrangement *of the pulltype solenoid utilized to swing the micro switch into contact with the cam depressions in the cutter head.

Fig.-24 is a partial, lon'g'itudinal seotionalView taken along the plane 2424 of Fig. 4 showing the arrangement of the locks 'utilized'for looking longitudinal movement of the sliding table and the forked cam utilized for actuating such locks.

Fig. 25 is aperspective view of the fixed wedge member utilized for locking the cutter.

Fig. "26 'is 'a perspective 'view of the movable Wedge member utilized for "lockingthecutter.

Fig-27 is a perspective view of the-cutter utilized for putting the threads in the stepped interior of the breech'ring.

Fig. 28 is a View showing diagrammatically the hydraulic 'and electrical system utilized for the operation of the breech ring threading machine.

"Fig. '29 is aside elevationalview "of the :guide rod utilized for guiding the "wedge "actuating spring.

The breech ring threading machine to be described herein in more detail utilizes a reciprocating spindle vertically mounted in a suitable housing. Reciprocation of the spindle is obtained by a crank connected to a crank shaft which is driven 'by-a suitable power source. A cutter head is'secured 'to the end of the reciprocating spindle which holds a multi-toothed thread cutter. The

reciprocation of the spindle is such as to permit the threading tool to describe an are slightly greater than the angular extent of the step to be threaded. Mechanisms for automatically advancing the cutter into the workpiece are contained within the spindle and cutter head. Such mechanism retracts the cutter on each return stroke .of the spindle. The leadzo'fthe thread being out within "the stepped interior of the breech ring is .produced by a lead screw and nut aiiixed to the upper end of the reciprocating spindle. Thus as theis'spindle reciprocates, such spindle will also be raised and lowered an amount governed by the lead'of the leadscrew and accordingly repro- 'ducing'suchlead'on'the threads being cut.

The breech'ring'to be step threaded is a substantially :cylindnical member and the specific ring. chosen for purposes of illustrating the operation of this machine is one adapted to be assembled to an 8" rifle. It should be understood however thal'tthis r in'gis only 'a specifioexamp'le and that any cylindrical member having Ia stepp'ed sur'face interior can be readily threaded or otherwise-machined by'this machine 'aswill be presently described. The breech ring utilized herein isjprovided' with a stepped interior having two sets of four stepsfeach set "howeverbeing or different height. A 'low and'a high step are provided adjacent each other and are disposed at degree arcs about the inner periphery of the breech ring, each combination of steps being separated by "an unthreaded notch 'to permit inser'tion of the breech block.

As .shown in Figs. 1 '2 "the threading machine comprisesa'table II and a housing I mounted thereon. Such housing comp-rises a column "2 and an overhanging "head "3 to mount and enclose the elements of the breech "ringthreading machine. The housing I may be either cast iron "or preferably of welded steel plate "cons'truction and is secured to table It byxsuitabl'e bolts. .table &8 'is-s.ubstan'tially rectangular inshape -and is preferabl constructed of welded steel plates. .In'the base of column 2 of housing I there is mounted inbear'ings 5 and ,a'horii.

zontalsha'it .6. .Ihebearing A is suitably mount ed and secured to one side of .c.01umn.-.2 while bearing 5 ..-is .mounted on .a suitable bracket "3' .which is preferably welded to the base of .col-

umn .2. The shaft i5 .is supported at its midsection by another bearing 8 mounted .in a web's provided on the inside-of column 52. Adja cent the extreme right end of shaft 6., .as viewed in Fi g. .2, a combination flywheel and pulley ii I is mounted on a spindle i3 which issuitablysupported inhousing =I Thespindle "i3 is connected to shaft 3 by conventional clutch id. i he clutch 'is mounted on the shaft 5 betweenthe bearings 3 and 3. Clutch "It is actuated by -:a

lever 15 mounted on :the outside "of column 2.

The pulley ii is connected -to a "suitable power source "(not shown)- -A crankshaft "I'S is vertically mounted "in the upper end of column 2. 'The'upper end-of crank shaft H6 is supported by'abearing I3 which rests on the -:counterbore'd portion or a cylindrical bearing support "I9 while the lower end of shaft I6 is supported by a thrust bearing i The bearing'support I9 is provided with an integral flange 20 which rests on the'top of 'head '3. An axial hole 2| is provided in bearing support It to receive crank shait I6. Thelower end of crankshaft I8 passes throrgh a boss 22 preferably 'welded'tothe bOttomof head 3. The "crank aasanu shaft I6 is arranged to be driven by pulley H by means of a train of gears connecting shaft 6 with crank shaft [6. A spur gear 42 suitably keyed to shaft 6 connects with a gear 43 mounted on a shaft 44 which is supported in bearings 45 and 46 in bracket 1 and web 9 respectively. Another gear 41 on shaft 44 connects with a gear 48 mounted on a horizontal shaft 49 which is like- Wise supported in bearings 50 mounted in the outside wall of column 2 and the web 9. A bevel gear 5| is suitably keyed to shaft 49 and meshes with a bevel gear 52 on the end of crank shaft I6. Thus by means of these connecting gears power is transmitted from the power source to the crank shaft l6.

In the forward overhanging portion of head 3 there is vertically mounted a spindle body 23 which is rotatably supported at its upper and lower ends by bearings 24 and 25 respectively. The spindle body 23 is a hollow cylindrical member and houses a spindle 26. A ring 21 is placed on top of bearing 25 which surrounds spindle body 23 and is placed adjacent a shoulder 28 on the end of spindle body 23. Shoulder 28 is formed by a slightly reduced end diameter of the spindle body 23. About the periphery of spindle body 23 there are provided twelve evenly spaced, radially disposed, vertical slots 250 (Fig. 5), for a purpose to be later described. There. are likewise provided twelve evenly spaced square headed pins 560 threaded into radial holes about the periphery of spindle body 23. Such pins are so positioned that two opposite corners of their squared heads are vertically disposed as shown in Fig. 6. Pins 560 are provided for indexing purdriving arm are bifurcated so that either may.

receive a connecting rod 33 between their bifurcated portions. The apexes 34 and 35 are each utilized as a point of application of driving forces fromcrank shaft |6 and are so spaced to permit.

two distinct degrees of reciprocation of the spindle as will be described. Atransverse pin 36 inserted thru suitable vertical holes in each of the bifurcated apexes connects such rOd to either The other end of connecting rod [6 in a convenapex 34 or 35. 33 connects with crank shaft tional manner. Connection is made between the driving arm 39 and spindle body 23 by a pinlike end of a piston 406 extending from a hydraulic cylinder 40l mounted on driving arm 39 as shown in Fig. 19.

The hydraulic cylinder 40| (Figs. 3- and 19) of conventional construction and is horizontally mounted within a recess 402 in driving arm 30.

Hydraulic cylinder 40| is sespindle body 23. cured to driving arm 30 by suitable bolts.

conventional solenoid-operated, two-way valve 406 (Fig. 28) is connected to cylinder 4M and is operated by two solenoids 401 and 408 each respectively mounted at opposite ends of valve 406. When solenoid 401 is energized as will be later.

thus forcing pin 400 outwardly into engagement with one of slots 250 in spindle body 23. When solenoid 401 is de-energized and solenoid 408 is energized, the direction of flow of hydraulic fluid is reversed. Such fluid enters the forward portion of cylinder 40| to reverse the direction of movement of hydraulic cylinder 40| which withdraws pin 400 from slot 250. The hydraulic fluid is. supplied to valve 406 and to all other control valves by a pump 4|0 mounted on the base of the breech ring threading machine. The pump M0 is preferably driven by an electric motor 4 and the motor and pump are mounted on top of a suitable reservoir tank 4|2.

Spindle 26 is a cylindrical member and is mounted within spindle body 23. The spindle 26.is keyed to the spindle body 23 by two oppositely disposed keys 31 (Fig. 6) provided at each end of spindle 26. An axial hole 38 in spindle 26 is counterbored to receive a lead screw 39. The lower end of spindle 26 is of reduced diameter and is provided with threads 26a (Fig.

5) on which a cutter head 65, to be later described, is mounted.

The .lead screw 39 is provided with an integral flange 39a near the lower edge thereof to vertil cally mount such screw within the upper counterbored portion of hole 38. Bolts 39b evenly spaced about the flange 39a secure the lead screw 39 to I the spindle 26. An axial hole 390 is provided in lead screw 39 to receive a rack 203 therethroughto be later described. Threads 39d are pro-- "vided on lead screw 39 which have a lead corresponding to the lead to 'be' produced on the threads cut on the interior stepped surfaces of abreech ring 64. A split lead nut 40 is screwed onto threads 39d of lead screw 39. Lead nut 40 .is split to provide convenient means for eliminating play or wear between the threads on nut 40 and lead screw 39. Bolts 40a connect the two halves of nut 40 and by tightening such bolts, nut 40 can readily be made to engage lead screw 39 4|a is placed on top of flange 4|. provided in flange 4| and washer 4|a to permit spindle 26 to be raised vertically thru head 3. On each side of hole 650 in flange 4| a guide shaft 53 is mounted in upstanding relation to flange 4|. Each shaft 53 is secured to flange 4| by a tapered pin 54. The yoke 55 is provided on each end with a boss 56 and in addition a large centrally located boss 51. A suitable hole 50 is provided in each boss 56 to slidably mount the yoke 55 on the shafts 53. Two collars 59 and 60 are placed about each shaft 53 between washer Ma and boss 56 and are secured to each shaft 53 by suitable screws. The collars 59 and 60 are provided to permit adjustment of the height of cutter head 65 with respect to the breech ring 64 for proper location of the threads to be out.

On top of yoke 55 a pair of hydraulic cylinders 62 are provided respectively surrounding each of shafts 53 and secured to yoke 55 by bolts 63 (Fig. 4). ventional structure and are provided to raise and lower spindle 26 and hence cutter head 65 in and out of cutting relationship with the workpiece as will be described. The lead nut 40 is secured to boss 51 on the underside of yoke 55 by bolts 6| which pass through suitable holes in yoke 55 and 1 The hydraulic cylinders 62 are of con- 

